Electrode system for proximity detection and hand-held device with electrode system

Abstract

An electrical hand-held device with proximity detection can be placed on a surface and has at least one transmission electrode, at least one reception electrode, and at least one compensation electrode between the transmission and reception electrodes. The transmission and compensation electrodes can be supplied with electric switching signals of predetermined frequency and amplitude. The electric switching signal at the compensation electrode is phase-delayed with respect to the electric signal at the transmission electrode. Alternating electric fields radiated at the transmission and compensation electrodes generate in the reception electrode a current that is representative of an approach of a hand to the hand-held device. The transmission and reception electrodes are arranged such that the impedance between the transmission and the reception electrodes exceeds a predetermined value suitable to keep the current generated in the reception electrode under a predetermined value.

The invention claimed is: 
     
       1. An electrical hand-held device that can be placed on a surface, comprising at least a transmission electrode, a reception electrode and a compensation electrode arranged between the transmission electrode and the reception electrode, with which an approach of a hand to the hand-held device is detectable,
 wherein from the transmission electrode a first alternating electric field and from the compensation electrode a second alternating electric field can be radiated wherein the first alternating electric field with respect to the second alternating electric field is phase-delayed and wherein the alternating electric fields can be coupled into the surface and into the reception electrode, 
 wherein the alternating electric fields coupled to reception electrode generate a current in the reception electrode that is representative of an approach of a hand to the hand-held device, 
 wherein the transmission electrode and the reception electrode on the hand-held device are arranged so that the sum of the impedances between the transmission electrode and the reception electrode that consist of
 the impedance between the transmission electrode and the surface, 
 the impedance of the surface and 
 the impedance between the surface and the reception electrode when a hand-held device is placed on the surface exceeds a predetermined value that is suitable to keep the current generated in the reception electrode under a predetermined value. 
 
 
     
     
       2. An electrical hand-held device that can be placed on a surface, comprising several electrode structures, each electrode structure comprising at least one transmission electrode, at least one reception electrode and at least one compensation electrode arranged between the transmission electrode and the reception electrode wherein with each of the several electrode structures an approach of a hand to the hand-held device is detectable wherein each of the several electrode structures is formed so that
 from the transmission electrode a first alternating electric field and from the compensation electrode a second alternating electric field can be radiated wherein the first alternating electric field with respect to the second alternating electric field is phase-delayed and wherein the alternating electric fields can be coupled into the surface and into the reception electrode, 
 the alternating electric fields coupled into the reception electrode generate a current in the reception electrode that is representative of an approach of a hand to the electrode structures on the hand-held device, and 
 transmission electrode and reception electrode at the hand-held device are arranged, that the sum of the impedances between the transmission electrode and the reception electrode that consist of
 the impedance between the transmission electrode and the surface, 
 the impedance of the surface and 
 the impedance between the surface and the reception electrode when the hand-held device is placed on the surface exceeds a predetermined value that is suitable, to keep the current generated in the reception electrode under a predetermined value I 0 . 
 
 
     
     
       3. The hand-held device according to  claim 2  wherein several electrode structures are coupled with an electronic evaluation device and wherein the electronic evaluation device is operable to evaluate an approach of a hand to each of several electrode structures. 
     
     
       4. The hand-held device according to  claim 3  wherein each of several electrode structures is respectively coupled with the electronic evaluation device by means of a multiplexer. 
     
     
       5. The hand-held device according to  claim 2  wherein transmission electrode, compensation electrode and reception electrode of each of several electrode structures are arranged at the hand-held device, that they do not touch the surface when a hand-held device is deposited on the surface. 
     
     
       6. The hand-held device according to  claim 5  wherein the transmission electrode, the compensation electrode and the reception electrode of each of several electrode structures are arranged on the surface of the hand-held device. 
     
     
       7. The hand-held device according to  claim 6  wherein the transmission electrode, the compensation electrode and the reception electrode of each of several electrode structures are arranged on the surface-oriented side of a hand-held device. 
     
     
       8. The hand-held device according to  claim 2  wherein in each of the several electrode structures the second alternating electric field radiated at the compensation electrode at least partially interferes with the first alternating electric field radiated at the transmission electrode and causes a level reduction of the alternating electric field resulting through the superposition, which leads to a reduction of the current generated in the reception electrode. 
     
     
       9. The hand-held device according to  claim 8  wherein in each of the several electrode structures a first approach of a hand to the hand-held device causes a change of the sum of the impedances between the transmission electrode and the reception electrode, comprised between the predetermined value Z 0  and a further predetermined value Z 1 , with Z 0 >Z 1 , and which is suitable to lead the current generated in reception electrode over the predetermined value I 0 . 
     
     
       10. The hand-held device according to  claim 9  wherein in each of several electrode structures a second approach of a hand to the hand-held device causes a change in the sum of the impedances between the transmission electrode and the reception electrode, which lies under a further predetermined value and which is suitable to lead the current generated at reception electrode over a second predetermined value I 1 , with I 1 >I 0 . 
     
     
       11. The hand-held device according to  claim 10  wherein at least the reception electrode of at least one of the several electrode structures is coupled to a control device that is so construed, as to cause
 a sleeping mode below the current I 0 , 
 a switch mode above the current I 0  and below the current I 1  and 
 an active mode above the current of the hand-held device. 
 
     
     
       12. The hand-held device according to  claim 11  wherein the transmission electrode, the reception electrode and the compensation electrode of each of the several electrode structures are so construed, that the approach of a hand to the hand-held device causes a level rise of the alternating electric field resulting from the superposition and a reduction of the impedance. 
     
     
       13. The hand-held device according to  claim 12  wherein the ratio of the level of the resulting alternating field in the first approach with respect to the level of the resulting alternating field in the second approach is smaller than the ratio of the impedance between the transmission electrode and the reception electrode in the second approach with respect to the impedance between transmission electrode and reception electrode in the first approach. 
     
     
       14. The hand-held device according to  claim 2  wherein the transmission electrode, the reception electrode and the compensation electrode of at least one of the several electrode structures are asymmetrically arranged in order to effect a left/right-distinction of an approach of a hand. 
     
     
       15. The hand-held device according to  claim 14  wherein depending on the distinction a predetermined device function can be performed. 
     
     
       16. The hand-held device according to  claim 2  wherein the second alternating electric field radiated from at least one compensation electrode of the several electrode structures is provided for an adaptation of the predetermined value to depending on the electric field surrounding a hand-held device. 
     
     
       17. The hand-held device according to  claim 3  wherein the evaluation electronics is so formed as to provide a representative signal of an approach to an electrode structure. 
     
     
       18. The hand-held device according to  claim 2  wherein the hand-held device is a remote control device. 
     
     
       19. The hand-held device according to  claim 2  wherein the hand-held device is a mobile phone. 
     
     
       20. The hand-held device according to  claim 2  wherein the hand-held device is an input device for a game console. 
     
     
       21. A hand-held device with:
 a housing, 
 a positioning or acceleration sensor to generate control data that correlate with a shifting of the housing to an X-axial direction and a Y-axial direction, and 
 a hand detection arrangement to generate signals that describe the approaching status of a hand facing the housing, wherein
 the hand detection arrangement comprises an electrode group with a transmission electrode, a compensation electrode and a reception electrode, and 
 a circuit arrangement coupled with these electrodes, 
 the circuit arrangement operable to supply the transmission electrode and the compensation electrode with signals such that a first alternating electric field is radiated from the transmission electrode and a second alternating electric field is radiated from the compensation electrode wherein the first alternating electric field with respect to the second alternating electric field is phase-delayed and wherein the alternating electric fields can be coupled into the reception electrode, and 
 a tapping circuit is provided for generation of an electrode signal that is conducted to a signal control unit implemented as a microcontroller unit. 
 
 
     
     
       22. The hand-held device according to  claim 21  wherein the impedance at the signal input of the tapping circuit reaches a minimum in the working frequency range. 
     
     
       23. The hand-held device according to  claim 21  wherein a signal is amplified such that the signal experiences an operational stable maximum when the amplifier has the smallest possible slope. 
     
     
       24. The hand-held device according to  claim 23  wherein subsequently a further signal amplification occurs and preferably wherein the output impedance of the tapping circuit is laid out so that a DC-output signal derived directly from the AC-input signal at the exit of the tapping circuit is performed. 
     
     
       25. The hand-held device according to  claim 24  wherein the DC-output signal of a signal control unit implemented as a microcontroller unit is conducted. 
     
     
       26. The hand-held device according to  claim 25  wherein the generator device is included directly into the signal control unit. 
     
     
       27. The hand-held device according to  claim 26  wherein the tapping circuit is attached to the signal control unit, that the first reinforcing step of the tapping circuit is actuated by a voltage-supplied signal control device. 
     
     
       28. The hand-held device according to  claim 21  wherein the signal control unit is so construed, as to cause of a sleeping mode and an active. 
     
     
       29. The hand-held device according to  claim 28  wherein in the sleeping mode coverage the detection of approaching status occurs at intervals, that are separated from each other through pauses. 
     
     
       30. The hand-held device according to  claim 21  wherein the hand-held device is a computer mouse, a remote control device, a mobile phone or an input device for a game console. 
     
     
       31. An electrode system for an arrangement at a hand-held device with at least a transmission electrode, a reception electrode and a compensation electrode wherein the compensation electrode can be arranged between transmission electrode and the reception electrode wherein the electrode system is formed so that
 from the transmission electrode a first alternating electric field and from the compensation electrode a second alternating electric field can be radiated wherein a first alternating electric field with respect to a second alternating electric field is phase-delayed and wherein alternating electric fields can be coupled into the reception electrode, and 
 alternating electric fields coupled with the reception electrode generate a current in the reception electrode that is representative of an approach of a hand to an electrode system. 
 
     
     
       32. The electrode system according to  claim 31  wherein the transmission electrode and the reception electrode can be arranged on the hand-held device, that the impedance between the transmission electrode and the reception electrode, when a hand-held device is placed on a surface exceeds a predetermined value that is suitable to keep the current generated in reception electrode under a predetermined value I 0 . 
     
     
       33. The electrode system according to  claim 32  wherein the impedance between the transmission electrode and the reception electrode is the sum of the impedances between the transmission electrode and the reception electrode, which consist of
 the impedance between transmission electrode and surface, 
 the impedance of surface and 
 the impedance between surface and reception electrode. 
 
     
     
       34. The electrode system according to  claim 31  wherein an electrode system can be coupled with an evaluation electronics and wherein the evaluation electronics is adapted, in order to evaluate an approach of a hand to the electrode system and to provide a representative signal for an approach. 
     
     
       35. A hand-held device with at least one electrode system according to  claim 31 .